Photographic products and processes with color shifted dye

ABSTRACT

Photographic products and processes for the imagewise generation of a dye from a color shifted dye precursor of a preformed image dye, said precursor having at least one ##STR1## group, wherein R is hydrogen, alkyl, provided that the α- carbon does not have a hydrogen atom attached thereto, aryl such as phenyl or substituted phenyl, e.g. p-nitrophenyl, or heterocyclic such as pyridine; R 1  -R 6  are hydrogen, alkyl, preferably having from 1 to 6 carbon atoms, or aryl; n is 0 or 1; and T is a moiety containing a thiazolidin-2-yl group which upon silver-assisted cleavage of said thiazolidin-2-yl group results in the formation of a ##STR2## group, which may be protonated under the reaction conditions, followed by cleavage of said ##STR3## which cleavage is anchimerically assisted or accelerated by said ##STR4## to provide after protonation, an ##STR5## group in a dye chromophore. In a preferred embodiment the precursor is a substantially colorless compound.

BACKGROUND OF THE INVENTION

This application relates to photographic products and processes forforming a dye image from a colorless precursor of a preformed image dyeand to novel compounds which are useful in such products and processes.

U.S. Pat. No. 3,719,489 describes and claims photographic processesemploying initially photographically inert compounds which are capableof undergoing cleavage in the presence of the imagewise distribution ofsilver ions made available during processing of a silver halide emulsionto liberate a reagent, such as, a photographically active reagent or adye in an imagewise distribution corresponding to that of said silverions. In one embodiment disclosed therein, color images are produced byusing as the photographically inert compounds, color providing compoundswhich are substantially non-diffusible in the photographic processingcomposition but capable of undergoing cleavage in the presence of theimagewise distribution of silver ions and/or soluble silver complex madeavailable in the undeveloped and partially developed areas of a silverhalide emulsion as a function of development to liberate a more mobileand diffusible color-providing moiety in an imagewise distributioncorresponding to the imagewise distribution of said ions and/or saidcomplex. The subsequent formation of a color image is the result of thedifferential in diffusibility between the parent compound and liberatedcolor-providing moiety whereby the imagewise distribution of the morediffusible color-providing moiety released in the undeveloped andpartially developed areas is free to transfer. Color-providing compoundsuseful in the above processes form the subject matter of U.S. Pat. No.4,098,783, a continuation-in-part, of said U.S. Pat. No. 3,719,489.

Compounds disclosed in the aforementioned patents are useful inliberating a reagent in the presence of said silver ions and/or silvercomplex are sulfur-nitrogen compounds containing the group ##STR6## or--S--X--N═ wherein X is ##STR7## These sulfur-nitrogen compounds may belinear or cyclic in structure, and in a particularly preferredembodiment are cyclic compounds, such as thiazolidine compounds whichcomprise a colored dye radical having a chromophoric system of an azo,anthraquinone, phthalocyanine or other dye and a thiazolidine-2'-ylmoiety which may be bonded directly to said dye radical or indirectlythrough an appropriate linking group. For example, the linking group maybe --CH₂ CH₂ O-- as in compound (33) at line 10, column 22, of said U.S.Pat. No. 3,719,489, or it may be CH₂ CH(CH₃)N< as in compound (34) incolumn 35 of said U.S. Pat. No. 4,098,783.

Copending commonly assigned U.S. application, Ser. No. 500,414, filedJune 2, 1983, now U.S. Pat. No. 4,468,450, discloses photographicprocesses and products for forming an image in dye from a colorlessprecursor of a preformed image dye which is substituted with a moietycontaining a thiazolidinyl group, said thiazolidinyl group (a) beingcapable of undergoing cleavage imagewise in the presence of an imagewisedistribution of silver ion and/or soluble silver complex and (b)possessing a substituent on the carbon atom in the 2-position which,upon cleavage of the thiazolidinyl group, undergoes a β-eliminationreaction followed by an intramolecularly assisted displacement reaction,which moiety maintains the precursor in its colorless form at leastuntil said thiazolidinyl group undergoes cleavage.

For a definition of a β-elimination reaction see J. March, AdvancedOrganic Chemistry, Reactions, Mechanisms and Structure, 2nd Ed., 1977,McGraw Hill, N.Y., pp. 895-922, particularly pp. 904-908. For adiscussion of anchimeric assistance see J. March, op cit pp. 280, 310and 311.

The present invention relates to photographic products and processeswhich exploit another sequence of reactions to form image dyes from acolor shifted dye precursor of a preformed image dye. According to thepresent invention the acyl group which color shifts or decolorizes thedye chromophore is independent of the assisting group thereby beingcapable of providing surprisingly faster generation of the image dye inthe photographic process.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide photographicproducts and processes for forming a dye image from a color shifted dyeprecursor of a preformed image dye.

It is another object to provide such products and processes for forminga dye image from a substantially colorless precursor of a preformedimage dye.

Another object is to provide such products and processes wherein saidcolor shifted dye precursor includes a thiazolidine group and thethiazolidine group undergoes imagewise silver-catalyzed cleavage in thepresence of an imagewise distribution of silver ion and/or solublesilver complex thereby initiating a sequence of reactions which providesthe image dye.

A further object is to provide novel compounds which are useful in saidproducts and processes.

BRIEF SUMMARY OF THE INVENTION

These and other objects and advantages are accomplished in accordancewith the invention by providing photographic products and processes forforming a dye image from a color shifted dye precursor of a preformedimage dye, said precursor having at least one ##STR8## group, wherein Ris hydrogen, alkyl, provided that the α-carbon does not have a hydrogenatom attached thereto, aryl such as phenyl or substituted phenyl, e.g.,nitrophenyl or a heterocyclic group such as pyridine; R₁ -R₆ are eachindependently hydrogen, alkyl, preferably having from 1 to 6 carbonatoms, e.g. methyl, isopropyl, etc., or aryl such as phenyl; n is 0 or1; and T is a moiety containing a thiazolidin-2-yl group which uponsilver assisted cleavage of said thiazolidin-2-yl group results in theformation of a ##STR9## group, which may be protonated under thereaction conditions, followed by cleavage of said ##STR10## whichcleavage is anchimerically assisted or accelerated by said ##STR11## toprovide, after protonation, an ##STR12## group in a dye chromophore. Ina preferred embodiment the color shifted dye precursor is asubstantially colorless compound.

The nitrogen-carbon bond in the ##STR13## moiety is stable to thealkaline photographic processing conditions in the absence of theanchimerically assisting or accelerating group and the introduction ofthe --COR group in the nitrogen containing dye has the effect of colorshifting or substantially decolorizing the dye.

Thus, the invention involves the use of color shifted, preferablysubstantially colorless, compounds which are precursors of a preformedimage dye and these compounds possess the property of remaining colorshifted or substantially colorless in the aqueous alkaline mediumpresent during the photographic development period as long as silver ionand/or soluble silver complexes are not present. However, these colorshifted compounds will be converted to their previous colored staterapidly during photographic processing when silver ions and/or solublesilver complexes are present in the alkaline medium.

These color shifted or substantially colorless compounds are obtained byshifting the absorption peaks of the preformed image dyes to a differentposition in the visible spectrum, or in the case of the substantiallycolorless compounds by shifting the absorption peaks which had been inthe visible region of the spectrum (400-700 nm) into the ultravioletregion (below 400 nm), by acylating the --NH group(s) which areresponsible for converting the chemical framework of the molecule into adye. The rate of cleavage of the acylamide group(s) to regenerate thedye is typically too slow for the conventional photographic processes inthe absence of an anchimerically assisting or accelerating nucleophilewhich is generated according to the invention by a silver-assisted orcatalyzed cleavage reaction.

The imagewise release of the anchimerically assisting or acceleratinggroup ##STR14## which acts to cleave the acyl group on the color shifteddye precursor thereby regenerating the colored dye species can beachieved through a β-elimination reaction or by ester hydrolysis from amoiety which is generated by silver-catalyzed cleavage of a thiazolidinegroup. The thiazolidine group is selected so as to have specificproperties which will make it useful in the photographic process. Theselection of the acyl group(s) is such that the acylamide color shiftedcompounds formed have adequate stability so that they remain colorshifted under the conditions of photographic development in the absenceof silver ion and/or soluble silver complexes but are cleaved rapidlywithin the required photographic time frame in the presence of silverion and/or soluble silver complex. Thus, by suitable selection of suchacyl groups in the synthesis of the color shifted dye precursorcompounds it is possible to control the rate of cleavage nd consequentlythe rate at which a dye image is formed according to the invention.

In one embodiment then, the present invention relates to a photographiccolor process which provides a dye image, the process involving thesteps of photoexposing a photosensitive element containing a silverhalide emulsion, the latter having associated with it a color shifteddye precursor of a preformed image dye, preferably a substantiallycolorless precursor, developing said exposed silver halide emulsion toform an image in developed silver and an imagewise distribution ofsilver ions and/or soluble silver complex in the partially developed andundeveloped areas of the emulsion and forming as a function of saiddevelopment a color dye image from said color shifted dye precursor.

The color shifted image dye-providing precursor compounds which areutilized in the photographic products and processes of the invention maybe represented by the formula

    D--T

wherein D is ##STR15## and D', together with ##STR16## is a preformeddye chromophore; and T, R₁ -R₆ and n are as previously defined.

In a preferred embodiment T can be represented by the group -L-T' whereT' is a thiazolidin-2-yl group and L is a moity capable of undergoing aβ-elimination reaction following cleavage of said thiazolidin-2-ylgroup, or of undergoing an ester hydrolysis reaction following cleavageof said thiazolidin-2-yl group.

β-Elimination reactions are well known in the art and involve thebreaking of bonds, for example, a C--N, C--O, C--S, C--Se, N--N, N--O orother bond to release a leaving group containing the hetero atom, whichin this instance would comprise ##STR17## that ultimately would releasethe dye by the anchimerically assisted or accelerated cleavage reaction.Cleavage of the thiazolidine group generates an aldehyde or aldiminiumion which activates the proton on the -carbon to attack by a base,leaving a pair of electrons free to move to the β-carbon and releasingthe leaving group from the β-carbon atom. Any moiety that undergoesβ-elimination may be employed as L in the compound formula aboveprovided that the elimination rate and the rate of the anchimericallyassisted or accelerated cleavage reaction taken with the silver assistedcleavage rate provides the image dye at a photographically useful ratein a given photographic system. The rate constants for various leavinggroups in elimination reactions of β-substituted sulphones,β-substituted phenyl ketones and β-substituted esters have been reportedby Charles J. M. Stirling et al, J. Chem. Soc. (B), 1970 pp. 672 and684; Charles J. M. Stirling et al, J. Chem. Soc. Chem. Comm., 1975, page941; and Charles J. M. Stirling, Acc. Chem. Res. 12, 1979 pp. 198-203.Examples of some leaving group from a carbon system include --SMe;--SPh; --SePh; --OPh, --OMe; --P(O) (OEt)₂ ; --N(Me)Ts; --N(Me)Ac;--N(Ph)Ac; --N(Ph)Ts; --N(Ph)CO₂ CH₂ Ph and --N(Me)CO₂ Ph wherein Me,Et, Ph, Ac and Ts represent methyl, ethyl, phenyl, acetyl, and tosylrespectively. However, the rate of elimination of the leaving groupaccording to the present invention is surprisingly faster than mighthave been expected in view of the reported values.

Thus, according to the invention, the β-elimination or ester hydrolysisreaction which occurs as a result of the cleavage of the thiazolidinylgroup is used to generate a neighboring, or leaving, group asillustrated above which anchimerically assists or accelerates thecleavage of the amide group ##STR18## to provide the imagewisedistribution of dye.

The image dye released from the color shifted dye precursor compoundsmay be any suitable dye having an --NH group or groups the acylating ofwhich markedly affects the absorption peak of the dye. Typical suitablegeneral classes of dyes include, for example, anthraquinone, acridine,azo, aminotriphenylmethane, xanthene and naphthoquinone dyes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

One class of preferred compounds according to the invention isrepresented by the formula ##STR19## wherein R₇, R₈ and R₉ may behydrogen, alkyl, preferably having from 1 to 6 carbon atoms; aryl suchas phenyl, aralkyl such as benzyl or phenethyl or alkaryl; R₁₀ may behydrogen or a group that can be removed upon cleavage of thethiazolidinyl group to leave an electron pair, e.g., a carboxy group;R₁₁ may be alkyl, aryl, aralkyl or alkaryl; R₁₂ may be hydrogen,carboxy, N,N-dialkylcarboxamido, alkyl, aryl, aralkyl or alkaryl; andR₁₃, R₁₄ and R₁₅ each may be hydrogen, alkyl, aryl, aralkyl or alkaryl.

Particularly preferred compounds within this class are represented bythe formulas ##STR20##

Another preferred class of compounds according to the invention isrepresented by the formula ##STR21## wherein R₁₆ may be alkylene having2 or 3 carbon atoms which may be further substituted with alkyl groupshaving from 1 to 6 carbon atoms which may form a ring or a fused ringsystem; or aryl such as phenyl to which the thiazolidine group and--CO-- are attached ortho to each other; and D', R₁ -R₁₅ and n arepreviously defined. ##STR22##

In the substituents noted above for R-R₁₆ typical aryl groups includephenyl and naphthyl; typical alkyl groups are preferably lower alkylhaving from 1 to 6 carbon atoms, for example, methyl, ethyl, isopropyl,etc.; typical aralkyl groups include phenyl-substituted alkyl whereinsaid alkyl preferably has from 1 to 6 carbon atoms; and typical alkarylgroups include alkyl-sbstituted phenyl wherein said alkyl preferably hasfrom 1 to 6 carbon atoms.

The compounds of the present invention may be synthesized according totechniques which are known in the art and these will be apparent fromthe specific examples provided herein.

As noted previously, the present invention is concerned with theformation of a color image from certain image dye-providing compoundscomprising a color shifted precursor of a preformed image dye. In thisembodiment, the image dye-providing compound may be present initially inthe photosensitive element in a layer or layers other than the layercontaining the light-sensitive silver halide emulsion, or it may be inthe light-sensitive layer itself. For example, it may be in a layer onone side of the emulsion or in two layers, one on either side of theemulsion. If desired, it may be separated from the emulsion layer by oneor more spacer layers. Where the image dye-providing compound is presentin the light-sensitive layer, the compound should be inert, that isphotographically innocuous in that it does not adversely affect orimpair image formation. If not photographically innocuous, the compoundmay be modified in a manner which does not interfere with thedevelopment process in any way, but which deactivates the compound sothat it does not affect adversely the light-sensitive emulsion. Ratherthan being disposed in the photosensitive element, the imagedye-providing compound may be initially contained in a layer associatedwith an image-receiving layer in processes such as diffusion transferprocesses where image-receiving elements are employed.

The formation of color images according to the subject invention isapplicable to the preparation of both monochromatic and multicolorimages. For example, the image dye-providing compounds of this inventionmay be employed in photographic systems utilizing multilayerphotosensitive elements comprising at least two selectively sensitivesilver halide emulsion strata having said image dye-providing compoundsassociated therewith which are processed simultaneously and withoutseparation to provide a multicolor image. In such a structure, a barrierinterlayer of silver complex scavenger, e.g., silver precipitant may beused, to confine diffusion of soluble silver complex to the appropriatestratum. Also, filter layers containing, e.g., bleachable filter dyes ofthe type described in U.S. Pat. Nos. 4,304,833, 4,358,118 and 4,304,834may be used to control the spectral composition of light falling on theunderlying light-sensitive layer. Another useful structure for obtainingmulticolor images is the screen type negative described in U.S. Pat. No.2,968,554 or that described in U.S. Pat. No. 3,019,124.

According to one method of forming color images, both the image dyes andtheir parent compounds comprising the color shifted precursor of apreformed image dye are substantially non-diffusible from their initialposition in association with the photosensitive strata. To achieve therequisite non-diffusibility, the parent compound may be appropriatelysubstituted with an immobilizing group, e.g., a long chain alkyl group,and the image dye released may be a dye that is substantiallynon-diffusible by nature or it may be rendered non-diffusible byappropriate substitution with an immobilizing group, by including amordant in the same layer with said image dye or by other means thatwould prevent the dye from diffusing from the photosensitive element.

Though the developed silver present in the photosensitive element afterimage formation and any remaining silver halide may be removed in aconventional manner, for example, by a bleach-fix bath, it is preferredto bleach the developed silver and to complex residual silver halide insitu. In a particularly preferred embodiment, the silver halide emulsionemployed is one which upon development contains low covering powersilver in the developed areas whereby the need for bleaching isobviated. In these embodiments, it will be appreciated that the silverhalide developing agents, the silver halide solvents and other reagentsemployed should be substantially non-staining.

Rather than forming monochromatic and multicolor images non-diffusiblefrom the photosensitive element, it will be appreciated that the imagedyes provided by the parent compounds may be diffusible to form thecolor image on a single common image-receiving layer. In thisembodiment, the subsequent formation of a color transfer imagepreferably employs a differential in diffusibility between the parentcompound and the liberated dye. This differential in diffusibility maybe achieved in a known manner by the appropriate selection of animmobilizing group(s), such as a long chain alkyl or alkoxy group and/orsolubilizing group(s), such as, hydroxy, carboxy or sulfo groups.

In the latter embodiments, where the image dyes released are diffusible,the photosensitive layer and the image-receiving layer may be inseparate elements which are brought together during processing andthereafter retained together as the final print or separated followingimage formation, or the photosensitive and image-receiving layers may bein the same element. For example, the image-receiving layer may becoated on a support and the photosensitive layer coated on the surfaceof the image-receiving layer. The processing composition may be appliedto the combined negative-positive element using a spreader sheet tofacilitate spreading the liquid composition in a uniform layer adjacentthe surface of the photosensitive layer. The image-receiving layercarrying the color image may be separated from the overlyingphotosensitive layer(s), e.g., with the aid of a stripping layer, or thecolor image may be viewed as a reflection print by employing alight-reflecting layer between the photosensitive and image-receivinglayers.

Illustrative of still other film units are those where the negative andpositive components together comprise a unitary structure and arelaminated and/or otherwise physically retained together at least priorto image formation. Generally, such film units comprise a plurality oflayers including a negative component comprising at least onelight-sensitive layer, e.g., a silver halide layer and a positivecomponent comprising an image-receiving layer which components arelaminated together or otherwise secured together in physicaljuxtaposition as a single structure.

Included among such structures are those adapted for forming a transferimage viewable without separation, i.e., wherein the positive componentcontaining the transfer image need not be separated from the negativecomponent for viewing purposes. In addition to the aforementionedlayers, such film units include means for providing a reflecting layerbetween the image-receiving and negative components in order to maskeffectively the silver image or images formed as a function ofdevelopment of the silver halide layer or layers and also to provide abackground for viewing the transfer image in the receiving component,without separation, by reflected light. This reflecting layer maycomprise a preformed layer of a reflecting agent included in the filmunit or the reflecting agent may be provided subsequent tophotoexposure, e.g., by including the reflecting agent in the processingcomposition.

The aforementioned layers are preferably carried on a support andpreferably are employed with another support positioned on the opposedsurface of the layers carried by the first support so that the layersare sandwiched or confined between the support members, at least one ofwhich is transparent to permit viewing of the final image. Such filmunits usually are employed in conjunction with means, such as, arupturable container containing the requisite processing composition andadapted upon application of pressure of applying its contents to developthe exposed film unit. Film units of this type are now well known andare described, for example, in U.S. Pat. Nos. 3,415,644, 3,415,645,3,594,164 and 3,594,165.

The processing composition employed comprises an aqueous solution andusually an aqueous alkaline solution of a silver halide developing agentand a silver halide solvent. The named ingredients may be presentintially in the aqueous medium or may be present initially in thephotographic film unit, for example, in the emulsion and/orimage-receiving and/or spacer layers as heretofore suggested in the art.When such ingredients are present initially in the film unit, theprocessing composition is formed by contacting the product with asuitable aqueous medium to form a solution of these ingredients. Thealkali employed may be any of the alkaline materials heretoforeemployed, such as sodium or potassium hydroxide.

The silver halide solvent also may be any of the heretofore knownmaterials, such as sodium or potassium thiosulfate, sodium thiocyanateor uracil; also the thioether-substituted uracils, pseudo-uracils andother compounds disclosed and claimed in U.S. Pat. No. 4,126,459; the1,3-disulfonylalkanes and cycloalkanes of U.S. Pat. Nos. 3,769,014 and3,958,992, respectively; or the alkanes containing an intralinearsulfonyl group and, e.g., an intralinear N-tosylsulfimido orN-tosylsulfoximido group as disclosed and claimed in U.S. Pat. No.4,107,176. Also, a silver halide solvent precursor may be used such asthose disclosed in U.S. Pat. No. 3,698,898 and as disclosed and claimedin copending U.S. patent application Ser. No. 382,479 filed May 27,1982.

Examples of silver halide developing agents that may be employed arehydroquinone and substituted hydroquinones, such as tertiary butylhydroquinone, 2,5-dimethyl hydroquinone, 4'-methylphenylhydroquinone;pyrogallol and catechols, such as catechol, 4-phenyl catechol andtertiary butyl catechol; aminophenols, such as2,4,6-diamino-orthocresol; 1,4-diaminobenzenes, such asp-phenylenediamine, 1,2,4-triaminobenzene and4-amino-2-methyl-N,N-diethylaniline; ascorbic acid and its derivatives,such as ascorbic acid, isoascorbic acid and 5,6-isopropylidene ascorbicacid and other enediols, such as, tetramethyl reductic acid;hydroxylamines, such as N,N-di-(2-ethoxyethyl)hydroxylamine,N,N-di-(2-methoxyethyl)hydroxylamine andN,N-di-(2-methoxyethoxyethyl)hydroxylamine; and heterocyclic compounds,such as, 1-phenyl-3-pryazolidone and4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidone.

Usually, though not necessarily, the processing composition includes aviscosity-increasing reagent such as a cellulosic polymer, e.g., sodiumcarboxymethyl cellulose, hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, etc; an oxime polymer, e.g., polydiacetoneacrylamide oxime; or other high molecular weight polymers.

In addition to the aforementioned ingredients, the processingcomposition also may contain antifoggants, preservatives and othermaterials as are conventionally used in the art.

The processing composition may be applied to the photosensitive element,for example, by coating, dipping, spraying or by the use of a rupturablecontainer or pod such as disclosed in U.S. Pat. No. 2,543,181, thecontainer being positioned in the film unit so as to be capable uponrupturing of spreading its contents in a substantially uniform layer.

The photosensitive element may be any of those conventionally employedand generally comprises a silver halide emulsion carried on a base, forexample, glass, paper or plastic film, such as cellulose triacetatefilm, polyethylene terephthalate film, polystyrene film and polyolefinfilms, e.g., polyethylene and polypropylene films. The silver halide maybe a silver chloride, iodide, bromide, iodobromide, chlorobromide, etc.The binder for the halide, though usually gelatin, may be a suitablepolymer such as polyvinyl alcohol, polyvinyl pyrrolidone and theircopolymers.

Depending upon the particular photographic system, a mordant for the dyeimage may be used in association with the photosensitive layers asdiscussed above, or a separate image-receiving element may be employed.The image-receiving layer, i.e., dyeable stratum may comprise any of thematerials known in the art, such as polyvinyl alcohol, gelatin, etc.,preferably containing a mordant for the transferred image dye(s). Thedyeable stratum can be in the same element as the photosensitive layeror it may be in a separate element as appropriate for a givenphotographic process.

In diffusion transfer processes employing an aqueous alkaline processingcomposition, it is well known to employ an acid-reacting reagent in alayer of the film unit to lower the environmental pH followingsubstantial dye transfer in order to increase the image stability. Forexample, the previously mentioned U.S. Pat. No. 3,415,644 disclosessystems wherein the desired pH reduction may be effected by providing anacid-reacting layer adjacent the dyeable stratum. These layers maycomprise polymers which contain acid groups, e.g., carboxylic acid andsulfonic acid groups, which are capable of forming salts with alkalimetals or with organic bases; or potentially acid-yielding groups suchas anhydrides or lactones. Preferably the acid polymer contains freecarboxyl groups. Alternatively, the acid-reacting reagent may be in alayer adjacent to the silver halide most distant from theimage-receiving layer. Another system for providing an acid-reactingreagent is disclosed in U.S. Pat. No. 3,576,625.

An inert interlayer or spacer layer may be disposed between thepolymeric acid layer and the dyeable stratum in order to control or"time" the pH reduction so that it is not premature and interferes withthe development process. Suitable spacer or "timing" layers for thispurpose are described with particularity in U.S. Pat. Nos. 3,362,819;3,419,389; 3,421,893; 3,455,686; and 3,575,701.

The acid-reacting layer and associated spacer layer are usuallycontained in the image-receiving element in systems wherein the dyeablestratum and photosensitive strata are contained on separate supports,e.g., between the support for the receiving element and the dyeablestratum. In integral film units, these layers may be associated with thedyeable stratum, e.g., on the side of the dyeable stratum opposed fromthe photosensitive element or, if desired, they may be associated withthe photosensitive strata, as is disclosed, for example, in U.S. Pat.Nos. 3,362,821 and 3,573,043. In film units such as those described inthe aforementioned U.S. Pat. Nos. 3,594,164 and 3,594,165, they also maybe contained on the spreader sheet employed to facilitate application ofthe processing composition.

In addition to the aforementioned layers, the film units may containadditional layers are commonly used in the art, such as a layer ofantihalation dye, and/or a layer of filter dye arranged betweendifferentially color-sensitive emulsion layers. Depending upon theparticular photographic system, it may be desirable to use anti-halationand filter dyes which become decolorized during photographic processing.

The invention will now be described further in detail with respect tospecific preferred embodiments by way of example, it being understoodthat these are illustrative only and the invention is not intended to belimited to the materials, conditions, process parameters, etc. recitedtherein.

EXAMPLE I Preparation of Compound A

Benzyl chloride (104 g, 1.0 m) was added dropwise to a solution of KOH(112 g, 2.0 m) in a mixture of 100 ml of xylene and 304 g of1,3-propanediol at 50°-60° C. The solution was then heated at 100° C.for 2 hours. Water (400 ml) was added to the cooled solution and themixture was extracted twice with 600 ml of methylene chloride. Thecombined methylene chloride extracts were washed three times with 400 mlof water, dried over MgSO₄, filtered and evaporated to a yellow oilwhich was distilled under vacuum. The 98°-106° C. (1.5 mm) fraction wascollected to give 88.7 g of 3-benzyloxypropanol.

To a solution of the alcohol (9.9 g, 0.06 m) in methylene chloride (120ml) deaerated with nitrogen, triethylamine (8.4 ml, 0.06 m) was addedwith stirring. The solution was cooled to -78° C., and methane sulfonylchloride (4.62 ml, 0.06 m) added dropwise. The resultant slurry waswarmed to 0° C., stirred two hours, stored overnight at 20° C. thenwashed with: 100 ml of ice water; 100 ml of ice cold 3% HCl; 100 ml ofice cold 1:1 saturated NaHCO₃ : water; and water. The methylene chloridelayer was dried over Na₂ SO₄ and evaporated without heating to give athick straw colored oil. Drying under high vacuum gave 14.79 g of themethane sulfonate product.

Alaninol (6.1 ml, 0.0765 m) was added dropwise to a suspension of 50%NaH (3.67 g, 0.0765 m) in 90 ml tetrahydrofuran and 20 ml CH₃ CN. Themixture was refluxed for 45 minutes with stirring and a solution of themethane sulfonate product (18.5 g, 0.0758 m) in 15 ml of CH₃ CN wasadded at the reflux temperature. Heating was continued for 21/2 hoursfollowed by standing overnight at room temperature. Ethyl ether (200 ml)was added to the solution which was then washed twice with 125 ml ofwater. The organic solution was then extracted with 150 ml of 5% HCl.The aqueous acid layer was separated, made alkaline with 100 ml of 10%NaOH and extracted twice with 75 ml of ether. The combined etherextracts were dried over Na₂ CO₃ and Norit, filtered and evaporated togive 7.8 g (48% yield) of the desired aminoether, as a yellow oil b.p.132°-134° C. (1.75 mm) of the formula ##STR23##

The structure was confirmed by ¹ H NMR spectra.

The crude aminoether (8.1 g) was dissolved in 60 ml of anhydrous ethanoland treated with 5 ml of ethanol saturated with HCl gas. Ethanol (35 ml)was then added to the salt solution. 10% Pd/C catalyst (150 mg) wasadded and the mixture was hydrogenerated in a Parr shaker at 45 lbs.pressure. The catalyst was filtered off and the ethanol evaporated on arotary evaporator to give the hydrochloride salt of the aminoalcohol.

The salt was dried under vacuum and dissolved in 30 ml ofdimethylformamide. NaOCH₃ (2.46 g) and anhydrous methanol (9 ml) wereadded to the solution with stirring. Argon was used to deaerate themixture. Leucoquinizarin (2.70 g, 0.0111 m) was added to the suspensionand it was heated to 85° C. for about 48 hours and then the mixture wasoxidized with air for about 48 hours.

When oxidized dye reaction mixture was added to 100 ml of 1% HCl theproduct oiled out. The product was extracted with methylene chloride andthe extracts evaporated to a viscous oil which was dried overnight undervacuum at 80° C. The crude dye was chromatographed on a silica gelcolumn to give 2.7 g (52% yield) of the diol dye of the formula##STR24##

Oxalyl chloride (1.25 ml) was added to 20 ml of dry methylene chlorideunder argon with stirring. The solution was cooled to -78° C., anddimethylsulfoxide (1.3 ml) added dropwise. After stirring for 5 minutesa solution of the pure diol dye (2.7 g) in 10 ml of dry methylenechloride was added dropwise. The resulting magenta solution was stirredfor 20 minutes at -78° C. Triethylamine (6.5 ml) was added dropwise withstirring to produce a suspension which was allowed to warm to 0° C.After 20 minutes methylene chloride (25 ml) was added and the mixturewashed with ice water. Additional methylene chloride (25 ml) was addedand the mixture washed twice with 50 ml of 1% HCl. The organic phase wasdried over Na₂ SO₄, filtered and evaporated to an oil.

The resultant oil was dissolved in 5 ml absolute ethanol and treatedwith triethyl orthoformate (5 ml) and 500 mg of toluene sulfonic acidmonohydrate. The slightly purple-blue solution was stirred overnight atroom temperature. The solution was neutralized with solid Na₂ CO₃ and anadditional ten drops of 10% Na₂ CO₃ solution was added. The mixture wasthen stirred for 1 hour, filtered and the solid washed well with etherand the combined filtrate and washings evaporated to an oil. Theresulting cyan oil was dried under high vacuum at 80° C. overnight togive 3.13 g of the diacetal dye.

Under argon, a solution of the diacetal dye (1 g) in 10 ml of ether and10 ml of acetic acid was cooled to 0° C. and treated with 500 mg of zincdust with vigorous stirring and shaking. After about 5 minutes thesolution was yellow-green. Another 15 ml of ether were added and thesolution filtered. A small amount of zinc dust was added and the etherand acetic acid removed under vacuum to give an oil. Under argon, theoil was dissolved in ether, treated with 1 ml of 10% Na₂ CO₃ solution,swirled occasionally for one half, and evaporated to give an oil.

Under a stream of argon, a solution of dicyclohexylcarbodiimide (2 g) in15 ml of methylene chloride was cooled to -78° C. and formic acid (731ml) was added dropwise with stirring. After 10 minutes the ureabyproduct was filtered off through a glass wool plug at -78° C. by argonpressure and the resulting solution added to the leuco dye oil dissolvedin 5 ml of methylene chloride at -78° C. The reaction mixture wasallowed to warm to room temperature, stirred overnight and the crudeproduct was chromatographed on silica gel with 15% acetone/85% methylenechloride (v/v) to give 0.64 g of the formylated bis acetal compound.

The bis acetal was dissolved in 15 ml of acetone and 1 ml of water and 1ml of polyvinylpyridine tosylate salt added. The reaction mixture wasrefluxed for 18 hours, the catalyst filtered off and washed well withacetone. The combined filtrates were evaporated and the resulting soliddissolved in methylene chloride, dried over MgSO₄, the drying agentremoved and the solution evaporated and dried under vacuum to give 475mg of the formylated bis aldehyde compound.

An aminoethanethiol salt (650 mg) of the formula ##STR25## was suspendedin a solution of the bis aldehyde compound (475 mg) in 9 ml of methylenechloride and the flask flushed with argon. Triethylamine (250 ml) wasadded dropwise. In about 5 to 10 minutes an orange solution formed.Molecular sieves (5A, 1 g) was added, the system flushed with argon andthe temperature raised to 40° C. and refluxed for 66 hours. The reactionsolution was washed twice with cold 1% HCl and once with water, driedover Na₂ SO₄ and evaporated to give an oil. The crude oil was trituratedwith 70% ethyl acetate/30% hexane (v/v) to leave a gum. The gum wasdissolved in methylene chloride and chromatographed on silica gel using70% ethyl acetate/30% hexane. The high R_(f) material was collected. Theeluent was evaporated and combined with the previous triturant. Thecombined solution was rechromatographed and upon evaporation and dryingunder vacuum an additional amount of the bis formyl thiazolidine tetraester was obtained.

The formylated anthraquinone thiazolidine ester (0.3 g) was dissolved in4 ml of CH₃ CN and 2 ml of ethanol and cooled to 0° C. 1N KOH (1.4 ml)was added dropwise and the solution stirred for 5 hours at roomtemperature. Water (25 ml) and Norite were aded and the mixture filteredthrough Celite to give a reddish solution. The solution was acidified topH 4 by dropwise addition of 1N HCl to give 0.176 g of a salmon coloredsolid after filtration and drying. This was shown by a mass spectrum tobe a compound A plus compound A monomethyl ester and a small amount ofthe bis ester.

The aminoether intermediate used in the synthesis of the compound is thesubject of copending application Ser. No. 644,911, filed on even dateherewith.

The synthetic procedure for formylating the bis aminoanthraquinone dyeforms the subject of copending application Ser. No. 644,914, filed oneven date herewith.

EXAMPLE II

Compound B was prepared substantially as described in Example I with theexception that valinol was used as the starting material in place ofalaninol.

EXAMPLE III Preparation of Compound C

A solution of aminoether (16.2 g, 0.0726 m) of the formula ##STR26## in50 ml of ethanol was treated with ethanol saturated with HCl gas untilthe pH was 1 (about 6 ml). 10% Pd/C (200 mg) was added and the materialwas hydrogenated in a Parr shaker at 40 lbs of pressure. After 30 lbs.uptake the catalyst was removed by filtration under nitrogen, washedwith ethanol, and the combined ethanol filtrate and washings evaporatedto give a light tan gum which was dried under vacuum at 45° C. for 5hours to give 11.8 g of the hydrochloric acid salt of the amino alcohol.

The amino alcohol salt (11.5 g, 0.068 m) was added to a 20 ml solutionof sodium methoxide (3.6 g) in dry dimethylsulfoxide followed by1,5-dichloroanthraquinone (3.0 g, 0.0108 m). The mixture was heated to105° C. under nitrogen with stirring for 72 hours. Methylene chloride(200 ml) was added to the cooled reaction mixture and the solution waswashed three times with 200 ml of water, with 200 ml of 5% HCl, andfinally 100 ml of water. The methylene chloride layer was separated anddried over MgSO₄, filtered, and evaporated to a magenta solid. The driedsolid was dissolved in methylene chloride and chromatographed on asilica gel column with 10% acetone/90% methylene chloride (v/v) elutentto give 2.3 g (45% yield) of a magenta solid ##STR27## λ max(2-methoxyethanol) 520 nm, ε=14,100.

A solution of dimethylsulfoxide (0.270 ml, 0.00381 m) in dry methylenechloride (8 ml) was cooled to -70° C. in an acetone/dry ice bath. Oxalylchloride (0.278 ml, 0.00319 m) was added from a syringe with stirringfor 5 minutes. A solution of the anthraquinone dye (0.6 g, 0.00127 m) in6 ml of dry methylene chloride was added from a syringe and the mixturestirred for 25 minutes. Triethylamine (1.06 ml, 0.00636 m) was added andthe mixture stirred for 20 minutes. The reaction was allowed to warm to10° C. during 45 minutes and 50 ml of methylene chloride was added. Thereaction mixture was poured into 150 ml of methylene chloride, and themethylene chloride solution washed with 100 ml of water, twice with 100ml of 1% HCl and then with 100 ml of water. The methylene chloride phasewas separated, dried over MgSO₄, filtered and evaporated to a magentaglass. The product was chromatographed on a silica gel column frommethylene chloride and then eluted with 2% acetone/methylene chloride togive 0.32 g (54% yield) of the bis aldehyde dye ##STR28##

The bis aldehyde dye (0.265 g, 0.000568 m) was dissolved under nitrogenin 5 ml of methylene chloride and treated with 0.354 g (0.00113 m) of anaminoethanethiol of the formula ##STR29## which was obtained from theHCl salt. The reaction mixture was stirred for four hours, 32 μl ofacetic acid added and stirring continued overnight. MgSO₄ (100 mg) wasadded and stirring continued for 6 hours. The reaction mixture wasdiluted with 20 ml of methylene chloride and filtered. The MgSO₄ waswashed with 30 ml of methylene chloride. The combined filtrates werewashed with 50 ml of water, dried with MgSO₄, filtered and evaporated togive a magenta glass. The magenta glass was dissolved in 10 ml ofmethylene chloride and chromatographed on a silica gel column with 30%acetate/hexane (v/v) eluent to give 0.447 g (75% yield) of theaminoanthraquinone dye of the formula ##STR30##

λ max (2-methoxyethanol) 520 nm, ε=13,400; 550 nm, ε=12,000.

The aminoanthraquinone dye (0.6 g, 0.000569 m) was dissolved in 10 ml ofdry methylene chloride and zinc dust (0.4 g) added. The mixture waspurged with nitrogen, cooled to -5° C. in an ice bath and 98% formicacid (0.343 ml) added from a syringe. The mixture was stirred for onehalf hour at -5° C. Under rapid flow of nitrogen additional zinc dust(0.5 g) was added. After 10 minutes the mixture turned an orange color.The mixture was cooled to -60° C. in an acetone/dry ice bath and asolution of 1.8 g (0.0091 m) of 1,3-dicyclohexylcarbodiimide in 12 ml ofdry methylene chloride added from a syringe. The mixture was allowed tostir at -50° C. for three hours and then overnight at room temperature.Methylene chloride (320 ml) was added and the zinc and precipitatedsolid filtered off and washed with 50 ml of methylene chloride. Thecombined methylene chloride fractions were washed with saturated NaHCO₃solution then with water, dried and evaporated to a glassy residue. Thecrude product was dissolved in 30 ml of carbon tetrachloride, cooled to0° C. and the precipitate filtered off. The carbon tetrachloridesolution was chromatographed on a silica gel column, eluted first with30% ethyl acetate/70% hexane (v/v), then with 50% ethyl acetate/50%hexane (v/v) and finally with 80% ethyl acetate/20% hexane (v/v) to give0.48 g (76% yield) of a yellow glass, the formylated anthraquinone bisthiazolidine ester.

λ max (2-methoxyethanol) 230 nm, ε=40,000; 280 nm, ε=10,000(s); 290 nm,ε=8200(s).

The formylated anthraquinone thiazolidine ester (0.35 g, 0.0003155 m)was dissolved in 4 ml of CH₃ CN and 2 ml of methanol, cooled to 5° C.,0.7 ml of 0.5N NaOH was added dropwise and the solution stirred at 5° C.for 4 hours. The solution was refrigerated overnight. An additional 0.7ml of 1N NaOH was added and the solution stirred for 4 hours at 5° C. Afurther 0.7 ml of 1N NaOH was added and the solution stirred at 5° C.for 4 hours. Water (20 ml) was added and the solution filtered. Thefiltrate was acidified to pH 4 with 1N HCl. A pink precipitate formed.Water (50 ml) was added and the solution extracted four times with 75 mlof ethyl acetate. The ethyl acetate extracts were dried over MgSO₄,filtered and evaporated to a pinkish solid. The crude product wasdissolved in ethyl acetate and precipitated with hexane to give about0.125 g of a pink solid. Evaporation of the hexane gave about 100 mg ofa redder material. A mass spectrum showed the product was compound Cmixed with mono ester and bis ester.

λ max (2-methoxyethanol) 296 nm, λ=7,600; 320 nm, ε=4,000.

The aminoethanethiol intermediate used in the preparation of compoundsA, B and C is disclosed and claimed in copending application Ser. No.644,913, of Paul McGregor and Myron Simon, filed on even date herewith.

EXAMPLE IV Preparation of Compound D

A solution of 2-aminoethanol (18.1 ml, 0.3 m) in 100 ml ofdimethylformamide was deaerated with nitrogen for one half hour.Leucoquinizarin (12.1 g, 0.05 m) was added to the solution in severalportions with stirring under nitrogen. An orange solution formed. Thesolution was stirred under nitrogen at 70°-75° C. for 6 hours and thenovernight at room temperature. The solution was heated at 80° C. for 8hours with air bubbling through it. The solid dye came out of solutionupon cooling to room temperature. The mixture was poured into 2 litersof water and the solid collected by filtration. The dye was washed withone liter of water, dried in air, dissolved in ethyl acetate andprecipitated out of solution with hexane. The resulting blue solid wascollected by filtration and dried under vacuum to give 13.3 g (81%yield) of ##STR31##

m.p. 238°-240° C., λ max (2-methoxyethanol) 590 nm (ε=15,500), 635 nm(ε=20,200).

Formic acid 97%, (51.6 ml) was added dropwise at room temperature over aone hour period to an acetic anhydride solution (122.4 ml). The mixturewas heated to 55° C. for 21/2 hours, cooled and the anthraquinone dye (5g, 0.0153 m) was added. The reaction mixture was heated at 50°-55° C.for 17 hours. The cooled reaction mixture was diluted with 150 ml ofmethylene chloride and poured thorugh a silica gel column wet withhexane. The column was eluted with methylene chloride to remove the monoformylated-product and then eluted with 10% acetone/90% methylenechloride (v/v) and then with 15% acetone/85% methylene chloride toobtain the desired yellow formylated compound, ##STR32##

The ester-amide was dried under vacuum to give 3.46 g (48.5% yield),m.p. 188°-189° C., λ max (2-methoxyethanol) 330 nm, ε=4,000.

The ester-amide (0.4 g, 0.000857 m) in a solution of 10 ml of ethanol, 1ml water, 10 ml acetone and 0.1 ml of 1N HCl was heated to reflux for 4hours, the reaction mixture cooled, poured into 50 ml of methylenechloride and then the dried organic phase was chromatographed on asilica gel column. The column was eluted with methylene chloride andthen with acetone to obtain the desired product which was vacuum driedovernight to give 0.18 g of a light yellow solid, the bis formamide diol##STR33##

m.p. 206°-209° C. (dec.) λ max (2-methoxyethanol) 251 nm, ε=43,200; 300nm, ε=5,200; 320 nm, ε=46,000.

The yellow bis formamide diol (0.642 g, 0.00168 m) was dissolved in 30ml methylene chloride and 5 ml acetone and 0.844 g (0.00336 m) of thethiazolidine acid ##STR34## was added. 1,3-dicyclohexylcarbodiimide(0.692 g, 0.00336 m) was added to the solution which was then stirred atroom temperature under nitrogen for 16 hours. The resulting ureaby-product was collected by filtration and washed with 100 ml ofmethylene chloride. The solution and washings were combined, evaporatedto about 15 ml and chromatographed on a silica gel column. The columnwas eluted with 5% acetone/95% methylene chloride, and the eluent wasevaporated to give 0.54 g of crude product, compound D.

The crude product (300 mg) was dissolved in 20 ml of methanol to which20 ml of water were then added. Upon standing a light yellow solidformed which was collected by and dried under vacuum to give 250 mg ofcompound D, a light yellow solid, m.p. 104°-107° C., λ max(2-methoxyethanol) 250 nm, ε=30,000.

EXAMPLE V

A film unit was prepared wherein a transparent polyester film base wascoated with the following layers in succession:

1. a mordant layer coated at a coverage of about 3229 mg/m² of a graftcopolymer comprised of 4-vinylpyridine (4VP) and vinylbenzyltrimethylammonium chloride (TMQ) grafted ontohydroxyethylcellulose (HEC) at a ratio HEC/4VP/TMQ of 2.2/2.2/1 andabout 54 mg/m² of 1,4 butanediol diglycidyl ether;

2. a layer comprising about 430 mg/m² of compound C and about 430 mg/m²of polyvinylpyrrolidone;

3. a silver iodobromide emulsion layer comprising about 130 mg/m² ofsilver and about 645 mg/m² of gelatin;

4. a layer of about 320 mg/m² of gelatin and about 27 mg/m² ofsuccindialdehyde.

The film unit was passed through a pair of rollers at a gap spacing of51 microns together with a transparent polyester film base cover sheetat room temperature without any exposure and processed with a processingposition made up as follows:

    ______________________________________                                                        Weight                                                                        Percent                                                       ______________________________________                                        NaOH              5.0                                                         Sulfolane         20.0                                                        Hydroxyethylcellulose                                                                           3.0                                                         Water             72.0                                                        ______________________________________                                    

The processed film unit was placed in a spectrophotometer and theabsorption spectrum was recorded repetitively over a period of time. Thetransmission density was measured at 520 nm (λ max for compound C).

    ______________________________________                                        Transmission Density                                                          ______________________________________                                               Initial 0.15                                                                  10 Minutes                                                                            0.22                                                                  38 minutes                                                                            0.28                                                           ______________________________________                                    

The experiment described above was repeated with the exception that 0.5%of sodium thiosulfate, a silver halide solvent, was added to theprocessing composition. At 10 minutes after processing the transmissiondensity of the film unit was 0.42. The addition of the silver halidesolvent to the processing composition caused a substantial increase inthe amount of dye transferred.

A film unit as described above was exposed through the base in the darkto a test target with blue light (4 mcs) and processed as above with aprocessing composition made up as follows:

    ______________________________________                                                             Weight                                                                        Percent                                                  ______________________________________                                        NaOH                   5.0                                                    Sulfolane              20.0                                                   Sodium thiosulfate     0.5                                                    4'-methylphenylhydroquinone                                                                          0.3                                                    Carboxymethyl Hydroxyethyl Cellulose                                                                 3.0                                                    Water                  71.2                                                   ______________________________________                                    

After an 8 minute imbibition period the film unit was dipped into 2%acetic acid solution to stop development, peeled apart and allowed todry. A well developed magenta image was obtained. The transmissiondensity at 520 nm was 0.33.

The D_(max) and D_(min) values to red, green and blue light,respectively were:

    ______________________________________                                                       D.sub.max                                                                          D.sub.min                                                 ______________________________________                                        Red              0.04   0.03                                                  Green            0.30   0.09                                                  Blue             0.11   0.05                                                  ______________________________________                                    

EXAMPLE VI

A photosensitive element was prepared comprising a transparent polyesterphotographic film base having the following layers coated therein insuccession.

1. about 430 mg/m² of the methyl ester precursor of compound A and about430 mg/m² of cellulose acetate hydrogen phthalate;

2. a silver iodobromide emulsion layer comprising about 130 mg/m² ofsilver and about 645 mg/m² of gelatin;

3. a layer comprising about 320 mg/m² of gelatin and about 27 mg/m² ofsuccindialdehyde.

A positive element was prepared comprising a transparent polyesterphotographic film support and a mordant layer as described in Example V.

The photosensitive element was exposed to a test target in the dark withblue light (4 mcs) and then passed, together with the positive element,through a pair of rollers at a gap spacing of 51 microns and processedwith a processing composition made up as follows:

    ______________________________________                                                             Weight                                                                        Percent                                                  ______________________________________                                        NaOH                   5.0                                                    Sulfolane              20.0                                                   Sodium Thiosulfate     0.5                                                    4'-methylphenylhydroquinone                                                                          0.3                                                    Carboxymethylhydroxyethylcellulose                                                                   3.0                                                    Water                  71.2                                                   ______________________________________                                    

After an imbibition period of 10 minutes the film unit was dipped in 2%acetic acid to stop development and dried. A well developed cyan imagewas obtained. The D_(max) and D_(min) values for red, green and bluelight respectively were:

    ______________________________________                                                       D.sub.max                                                                          D.sub.min                                                 ______________________________________                                        Red              0.55   0.17                                                  Green            0.30   0.21                                                  Blue             0.14   0.18                                                  ______________________________________                                    

EXAMPLE VII

A photosensitive element was prepared wherein a transparent polyesterphotographic film support was coated with the following layers insuccession:

1. a layer comprising about 430 mg/m² of compound D and about 430 mg/m²of cellulose acetate hydrogen phthalate;

2. a silver iodobromide emulsion layer coated at a coverage of about 129mg/m² of silver (1.6 microns) and about 646 mgs/m² of gelatin;

3. a layer comprising about 323 mg/m² of gelatin and about 27 mg/m² ofsuccindialdehyde.

A positive sheet was prepared comprising a transparent polyesterphotographic film base on which the following layers were coated insuccession:

1. as a polymeric acid layer approximately 9 parts of a 1/2 butyl esterof polyethylene/maleic anhydride copolymer and 1 part ofpolyvinylbutyral coated at a coverage of about 26910 mg/m² ;

2. a timing layer comprising about 2570 mg/m² of a 60-29-6-4-0.4pentapolymer of butylacrylate, diacetone acrylamide, methacrylic acid,styrene and acrylic acid;

3. a polymeric image receiving layer of: (a) 3 parts of a mixture of 2parts polyvinylalcohol and 1 part of poly-4-vinylpyridine and (b) 1 partof a graft copolymer comprised of 4-vinylpyridine (4VP) andvinylbenzyltrimethyl-ammonium chloride (TMQ) grafted onto hydroxy-ethylcellulose (HEC) at a ratio of HEC/4VP/TMQ of 2.2/2.2/1 coated at acoverage of about 3220 mg/m²).

The photosensitive and positive elements were passed together through apair of rollers at a gap spacing of 51 microns and processed with aprocessing composition made up as follows:

    ______________________________________                                                          Weight                                                                        Percent                                                     ______________________________________                                        NaOH                10.0                                                      Sodium Thiosulfate  1.0                                                       Carboxymethylhydroxyethyl                                                                         2.0                                                       cellulose                                                                     Water               87.0                                                      ______________________________________                                    

After an imbibition period of 10 minutes the film unit had atransmission density of 0.17. The film unit had a uniform cyan color.

Although the invention has been described with respect to specificpreferred embodiments, it is not intended to be limited thereto butrather those skilled in the art will recognize that variations andmodifications made by made therein which are within the spirit of theinvention and the scope of the appended claims.

What is claimed is:
 1. A photographic color process which provides a dyeimage comprising the steps of photoexposing a photosensitive elementcontaining a silver halide emulsion, said silver halide emulsion havingassociated therewith a color shifted precursor of a preformed image dye,developing said exposed silver halide emulsion to form an image indeveloped silver and an imagewise distribution of silver ions and/orsoluble silver complex in the partially developed and undeveloped areasof said emulsion, and forming as a function of said development a colorimage in dye from said color shifted precursor, said color shiftedprecursor having at least one ##STR35## group wherein R is hydrogen,alkyl, provided that the α-carbon is not attached to a hydrogen atom, oraryl; R₁, R₂, R₃, R₄, R₅ and R₆ are each independently hydrogen, alkylor aryl; n is 0 or 1; and T is a moiety containing a thiazolidin-2-ylgroup, said thiazolidin-2-yl group being capable of undergoing cleavagein the presence of said silver ions and/or soluble silver complex, saidmoiety maintaining said color shifted precursor in its color shiftedform at least until said thiazolidin-2-yl group undergoes said cleavage.2. A photographic process as defined in claim 1 wherein said colorshifted dye precursor is substantially non-diffusible from the layer inwhich it is positioned during said photoexposure.
 3. A photographicprocess as defined in claim 2 wherein said color shifted dye precursoris positioned in said silver halide emulsion during photoexposure.
 4. Aphotographic process as defined in claim 1 wherein said image dyeprovided by said color shifted dye precursor is diffusible and furtherincluding the step of transferring said image dye to an image receivinglayer in superposed relationship with said silver halide emulsion.
 5. Aphotographic process as defined in claim 4 wherein a light reflectinglayer is provided between said silver halide emulsion and said imagereceiving layer whereby said dye image may be viewed against said lightreflecting layer, said light reflecting layer being effective to masksaid developed silver halide emulsion from one viewing said dye image.6. A photographic process as defined in claim 1 wherein said silverhalide emulsion is a negative working silver halide emulsion whereby apositive image is formed as a function of development.
 7. A photographicprocess as defined in claim 1 wherein said color shifted dye precursoris a substantially colorless compound.
 8. A photographic productcomprising a photosensitive element comprising a plurality of layersincluding a support, a silver halide emulsion in a layer on saidsupport, and in a layer on the same side of said support as said silverhalide emulsion, a color shifted precursor of a preformed image dye,said color shifted precursor having at least one ##STR36## group,wherein R is hydrogen, alkyl, provided that the α-carbon is not attachedto a hydrogen atom, or aryl; R₁, R₂, R₃, R₄, R₅ and R₆ are eachindependently hydrogen, alkyl or aryl; n is 0 or 1, and T is a moietycontaining a thiazolidin-2-yl group, said thiazolidin-2-yl group beingcapable of undergoing cleavage in the presence of silver ions and/orsoluble silver comlplex, said moiety maintaining said color shiftedprecursor in its color shifted form at least until said thiazolidin-2-ylgroup undergoes said cleavage.
 9. A photographic product as defined inclaim 8 wherein said color shifted precursor is non-diffusible inaqueous alkaline solution.
 10. A photographic product as defined inclaim 8 wherein said image dye provided by said color shifted precursoris non-diffusible in aqueous alkaline solution.
 11. A photographicproduct as defined in claim 8 wherein said image dye provided by saidcolor shifted precursor is diffusible in aqueous alkaline solution andfurther including an image receiving layer so positioned as to becapable of receiving by diffusion an imagewise distribution of saidimage dye.
 12. A photographic product as defined in claim 11 and furtherincluding means for applying an aqueous alkaline processing compositionto provide an aqueous alkaline solution of a silver halide developmentagent and a silver halide solvent.
 13. A photographic product as definedin claim 12 which includes a light reflecting layer between said silverhalide emulsion and said image receiving layer, whereby said dye imageformed by said imagewise distribution of diffusible dye may be viewed byreflection, said light reflecting layer being effective to mask saiddeveloped silver halide emulsion from one viewing said dye image.
 14. Aphotographic product as defined in claim 8 wherein said color shifteddye precursor is positioned in said silver halide emulsion layer.
 15. Aphotographic product as defined in claim 8 which includes a silverhalide developing agent in said silver halide emulsion layer.
 16. Aphotographic product as defined in claim 15 which includes a silverhalide solvent in a layer on the same side of the support as said silverhalide emulsion.
 17. A photographic product as defined in claim 8wherein said silver halide emulsion is a negative working emulsion. 18.A photographic product as defined in claim 8 which further includes anacid-reacting layer.
 19. A photographic product as defined in claim 8wherein said color shifted dye precursor is a substantially colorlesscompound.
 20. A photographic process as defined in claim 1 wherein saidcolor shifted precursor is a compound represented by the formula##STR37## wherein R is hydrogen, alkyl, provided that the α-carbon isnot attached to a hydrogen atom, or aryl; R₁, R₂, R₃, R₄, R₅ and R₆ areeach independently hydrogen, alkyl or aryl; A is ##STR38## R₇, R₈ and R₉are each independently hydrogen, alkyl, aryl, aralkyl or alkaryl; R₁₀ ishydrogen or carboxy; R₁₁ is alkyl, aryl, aralkyl or alkaryl; R₁₂ ishydrogen, carboxy, dialkylcarboxamido, alkyl, aryl, aralkyl or alkaryl;R₁₃, R₁₄ and R₁₅ are each hydrogen, alkyl, aryl, aralkyl or alkaryl; R₁₆is alkylene having 2 or 3 carbon atoms or aryl; n is 0 or 1; m is 1 or2; and p is 0, 1 or
 2. 21. A photographic product as defined in claim 8wherein said color shifted precursor is a compound represented by theformula ##STR39## wherein R is hydrogen, alkyl, provided that theα-carbon is not attached to a hydrogen atom, or aryl; R₁, R₂, R₃, R₄, R₅and R₆ are each independently hydrogen, alkyl or aryl; A is ##STR40##R₇, R₈ and R₉ are each independently hydrogen, alkyl, aryl, aralkyl oralkaryl; R₁₀ is hydrogen or carboxy; R₁₁ is alkyl, aryl, aralkyl oralkaryl; R₁₂ is hydrogen, carboxy, dialkylcarboxamido, alkyl, aryl,aralkyl or alkaryl; R₁₃, R₁₄ and R₁₅ are each hydrogen, alkyl, aryl,aralkyl or alkaryl; R₁₆ is alkylene having 2 or 3 carbon atoms or aryl;n is 0 or 1; m is 1 or 2; and p is 0, 1 or 2.